The plan to establish the UK as the world's largest producer of offshore energy faces one challenge more daunting than any other – what happens when the wind stops?

Critics of renewable energy argue that the unreliable nature of wind energy means the idea of a fossil fuel-free economy remains an environmentalist pipe dream.

But according to the Carbon Trust's Phil de Villiers the sheer scale of the UK's offshore energy capacity means concerns about reliability are largely unfounded. "It's very rare we have calm spells across all UK waters," he notes, adding that when calm spells occur the interconnectors that allow Britain to export energy would also allow it to import power from hydroelectric plants in the Nordics.

A recent report from PricewaterhouseCoopers predicts the formation of a pan-European "supergrid" would allow the entire continent to operate using 100% renewable electricity. "It is possible to envisage one offshore grid in north-western Europe and another in the Mediterranean bringing energy from African solar farms," explains PWC's Ronan O'Regan. "The challenge is co-ordinating planning across the EU, but it is feasible if there is sufficient investment in the grid."

Meanwhile, new grid management technologies promise to keep the lights on as we shift towards more renewable energy. For example, the Energy Technologies Institute recently announced a research project into energy storage systems, such as large-scale flow batteries and fly wheels, while proposals for new pumped hydro electric plants in Scotland could similarly store renewable energy for use at times when output falls.

Even the humble fridge could improve the reliability of the UK's energy grid. A number of firms are working on so-called dynamic demand technologies, capable of automatically powering down appliances such as fridges or dishwashers for a few minutes during periods of peak demand, reducing pressure on the grid.